Project Summary We propose to develop a non-invasive method to predict mammalian oocyte quality by analyzing the surrounding cumulus cells' gene expression patterns (cGEP). The result of the cGEP assay---a cGEP score--- can be used to predict embryo quality and ultimately the embryo transfer (ET) results. This technology, if success, will for the first time, provide a quantitative measurement of the in vitro fertilized IVF) embryos. It will help users to non-invasively identify the best embryo for transfer. Single embryo transfer is expected to decrease the frequencies of multiple gestations (i.e., increase the frequencies of singletons) in human IVF practices. Multiple gestations are associated with low birth weight babies, preterm births and maternal complications. While the increasing use of Assisted Reproductive Technology (ART) over the past two decades has helped thousands of infertile couples to have children, almost one third of ART pregnancies are twins or higher order multiple gestations; 51% of all ART neonates are the products of multiple gestations, a frequency 15- to 20-fold greater than with spontaneous conceptions. In many IVF and intracytoplasmic sperm injection (ICSI) procedures, more than one embryo is transferred to ensure satisfactory pregnancy results. This is largely due to the inability to accurately select good embryos by morphology examinations alone, the major judgment method in most IVF clinics. In fact, up to 40% of embryos with normal morphology have abnormal chromosomes. Such practices (transferring multiple embryos) contribute greatly to the high percentage of multiple gestations in ART. The ultimate goal of the present project is to develop a non-invasive method to predict oocyte and embryo quality in human IVF practices, in a 24-48 h turnover time. With this technology, when oocytes are collected and subjected to IVF procedures, the cumulus cells from each individual oocyte can be used for cumulus gene expression pattern (cGEP) assay. A cGEP score will be generated for each oocyte; consequently, each embryo generated from this IVF session will have a corresponding cGEP score. The cGEP score will assist users to make wise decisions on how and when to transfer the embryos. To our knowledge, this application represents one of the first commercial attempts to develop a non-invasive technology to predict human embryo quality. Cumulus cells are abundant and are considered to be disposable byproducts of oocyte retrieval for IVF treatment. Collection and analysis of cumulus cells is non-invasive and does not harm the oocyte. Biomarkers from cumulus cells can be used for diagnosis of infertility or reproductive toxicity. They can be used to improve the efficiency and efficacy of infertility treatments by identifying the most viable oocytes for fertilization in vitro, as well as exclusion of bad embryos for transfer. This will reduce the ned for and side effects associated with hyperstimulation of ovarian development during IVF. By limiting the number of oocytes needed for fertilization, fewer extra embryos will be generated, which avoids the ethical and social complications of handling and disposing of these extra embryos. It will also reduce the number of embryos transferred, thus reducing the risk associated with high-order multiple gestations. Multiple gestations are associated with low birth weight babies, preterm births and maternal complications 1. Reducing the frequencies of multiple gestations would not only reduce these clinical complications of the mothers and the newborns, but also reduce the medical costs associated with them.